91 And the fifth messenger did sound, and I saw a star out of the heaven having fallen to the earth, and there was given to it the key of the pit of the abyss, 2 and he did open the pit of the abyss, and there came up a smoke out of the pit as smoke of a great furnace, and darkened was the sun and the air, from the smoke of the pit. 3 And out of the smoke came forth locusts to the earth, and there was given to them authority, as scorpions of the earth have authority, 4 and it was said to them that they may not injure the grass of the earth, nor any green thing, nor any tree, but—the men only who have not the seal of God upon their foreheads, 5 and it was given to them that they may not kill them, but that they may be tormented five months, and their torment 'is' as the torment of a scorpion, when it may strike a man; 6 and in those days shall men seek the death, and they shall not find it, and they shall desire to die, and the death shall flee from them.
Matthew Henry's Commentary on Revelation 9:1-6
Commentary on Revelation 9:1-12
(Read Revelation 9:1-12)
Upon sounding the fifth trumpet, a star fell from heaven to the earth. Having ceased to be a minister of Christ, he who is represented by this star becomes the minister of the devil; and lets loose the powers of hell against the churches of Christ. On the opening of the bottomless pit, there arose a great smoke. The devil carries on his designs by blinding the eyes of men, by putting out light and knowledge, and promoting ignorance and error. Out of this smoke there came a swarm of locusts, emblems of the devil's agents, who promote superstition, idolatry, error, and cruelty. The trees and the grass, the true believers, whether young or more advanced, should be untouched. But a secret poison and infection in the soul, should rob many others of purity, and afterwards of peace. The locusts had no power to hurt those who had the seal of God. God's all-powerful, distinguishing grace will keep his people from total and final apostacy. The power is limited to a short season; but it would be very sharp. In such events the faithful share the common calamity, but from the pestilence of error they might and would be safe. We collect from Scripture, that such errors were to try and prove the Christians, 1 Corinthians 11:19. And early writers plainly refer this to the first great host of corrupters who overspread the Christian church.